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"I'm on the 35th floor, just relay to the command post I'm trying to get up," the voice of a fire captain says.

The brave fire captain was lost along with his 10 men. The mangled hulk of the Ladder 3 truck is all that's left from that day nearly 13 years ago. It's story, though, is told through the human stories and artifacts at the museum.

Some memories are from the Pentagon and Flight 77 - a melted Rolodex, a clock frozen in time. The watch was worn by Todd Beamer as he led a revolt aboard the hijacked plane headed for D.C.

Those touring the 9/11 memorial on Wednesday, which surrounds the new museum, say it will be a hard but important place to visit.

"Its totally overwhelming," said Deb Truran. "Everything that happened - it's a good reminder, what we have here."

"We have children. Its a place to go - a place where they can see it, understand it," said Greg Bennell.

The museum stands in the shadow of the towering new One World Trade Center, on the exact ground occupied by the twin towers, its exhibits seven stories down, at bedrock.

"It's a part of history and everybody should know about it, just like all the other history over the years," said Kevin Hartnett. "It's gotta be talked about and remembered."